The use of one or more consecutive condenser rollers on nonwoven cards is known. US2004/0154137A1, for instance, describes a nonwoven card provided with condenser rollers, also called stuffer rollers. Condenser rollers are positioned immediately downstream of a doffer roller. The doffer roller is taking the web from a main cylinder or from a randomizing roller. The doffer roller transfers the fiber web to a condenser roller. Because of the lower surface velocity of the condenser roller compared to the doffer roller, the fiber web is condensed, meaning it increases in weight per unit of surface area; and the fiber orientation in the web is affected. It is possible that a second condenser roller is installed to take off the web from the first condenser roller. Such second condenser roller has a lower surface speed than the first condenser roller, resulting in a further condensing of the fiber web. Typically, a take-off roller is taking off the fiber web from the last condenser roller. The take-off roller is normally the last roller on the nonwoven card covered with card wire.
The condenser roller or condenser rollers are provided with a specific type of card wire. The wires are mounted on the condenser rollers such that the tips of the teeth are oriented in the direction opposite to the rotation of the condenser roller. Card wires for condenser rollers mostly have a relatively large height, a rather large tooth depth, a slender tooth and a large pitch between teeth in order to be able to accommodate the amount of fibers of fiber web being produced.
WO2013/037711A1 discloses a card wire comprising an elongated rib portion and teeth. The teeth have a front portion and a back portion. The teeth hang over towards their front portion. The front portion and back portion merge at the tip of the tooth. The front portion comprises at least three sections: a first section extends from the tip of the tooth in the direction of the rib portion, a second section extends below the first section in the direction of the rib portion and a third section extends from the end of the second section in the direction of the rib portion. The second section comprises a straight part and a curved segment, wherein the straight part has a minimum length of 0.10 mm and the straight part has an angle between 10 and 30 degrees relative to the length direction of the card wire. The straight part is followed by the curved segment wherein the curved segment has a radius of at least 0.18 mm. The front portion can comprise downwards towards the rib portion of the second section at least one additional such second section. The document mentions the use of such card wires on condenser rollers of nonwoven cards.
US2013/133159A discloses a wire profile with a rib portion and a plurality of teeth over the length of the rib portion. The plurality of teeth is inclined at an angle with respect to the rib portion. The teeth have a front portion and a back portion. The front portion is the inner portion of the teeth leaning towards the rib portion and the back portion is the outer portion of the teeth. At least one tooth comprises at least one nose cut segment in its back portion. The wire can be beneficially used for covering condenser rollers.
WO2011/138322A1 discloses a wire profile for card clothing comprising a rib portion and plurality of teeth over the length of the rib portion. The teeth are sloped with a back slope representing the backbone of the teeth and a front slope representing the side in direct contact with fibers. The back slope has a tangent forming a back angle with the rib portion. The front slope is divided into at least two segments, a tip segment and an undercut segment to retain the fibers. The tip segment converges with the back slope to form a tip of the teeth wherein the tip segment serves to penetrate between fibers and wherein the tip segment has a tangent forming a tip angle with the rib portion. The undercut segment has a tangent forming an undercut angle with the rib portion; the undercut angle is at each point in the undercut segment larger than the maximum of the back angle and smaller than the smallest value of the tip angle.